title: Stability and in vitro digestibility of emulsions containing lecithin and whey proteins.
abstract: The effect of pH and high-pressure homogenization on the properties of oil-in-water (O/W) emulsions stabilized by lecithin and/or whey proteins (WPI) was evaluated. For this purpose, emulsions were characterized by visual analysis, droplet size distribution, zeta potential, electrophoresis, rheological measurements and their response to in vitro digestion. Lecithin emulsions were stable even after 7 days of storage and WPI emulsions were unstable only at pH values close to the isoelectric point (pI) of proteins. Systems containing the mixture of lecithin and WPI showed high kinetic instability at pH 3, which was attributed to the electrostatic interaction between the emulsifiers oppositely charged at this pH value. At pH 5.5 and 7, the mixture led to reduction of the droplet size with enhanced emulsion stability compared to the systems with WPI or lecithin. The stability of WPI emulsions after the addition of lecithin, especially at pH 5.5, was associated with the increase of droplet surface charge density. The in vitro digestion evaluation showed that WPI emulsion was more stable against gastrointestinal conditions.
authors.affiliation: Department of Food Engineering, Faculty of Food Engineering, University of Campinas (UNICAMP), 13083-862 - Campinas, SP, Brazil.
authors.forename: Raphaela Araujo
authors.initials: RA
authors.lastname: Mantovani
authors.forename: Ângelo Luiz Fazani
authors.initials: ÂL
authors.lastname: Cavallieri
authors.forename: Flavia Maria
authors.initials: FM
authors.lastname: Netto
authors.forename: Rosiane Lopes
authors.initials: RL
authors.lastname: Cunha
mesh_terms: D004355:Drug Stability; D004591:Electrophoresis, Polyacrylamide Gel; D045703:Emulsifying Agents / Q000032:analysis*; D004655:Emulsions / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D054709:Lecithins / Q000032:analysis*; D008894:Milk Proteins / Q000032:analysis*; D012212:Rheology; D013024:Soybean Oil / Q000737:chemistry; D014867:Water / Q000737:chemistry; D000067816:Whey Proteins
chemical_list: D045703:Emulsifying Agents; D004655:Emulsions; D054709:Lecithins; D008894:Milk Proteins; D000067816:Whey Proteins; D014867:Water; D013024:Soybean Oil